1. Field of the Invention
The present invention relates to an image display system for presenting an image on a screen in response to a position indicated by a pointer.
2. Description of the Related Art
There are conventionally available projection-type image display systems for use in presentations and conferences. By directly inputting coordinates using a pointer on the screen of a large display, a computer connected to the display is controlled. Characters and drawings are thus input. Some typically available systems incorporate a video camera in a projection-type display apparatus. The video camera picks up an emitter of the pointer, detects the position of the pointer, and a coordinate signal is then sent to the connected computer.
The brightness level on the screen of the projection-type display is raised to a level high enough to be used even in a lighted room. As computers are in widespread use, the demand on the projection-type display apparatus of this sort is mounting. In particular, a front projection apparatus is useful because of its portability, and varying image magnification in response to an available screen size.
However, since an operator needs to use a pointer in front of the screen in the front projection apparatus, the screen is shadowed by the pointer and the operator, and a cursor can become invisible.
Accordingly, it is an object of the present invention to provide an image display system which is smoothly operated and projects an image which is pointed at by a pointer but not overshadowed by the pointer.
To achieve the above object, in one aspect, an image display system of the present invention for displaying an image on a screen in response to a position of a pointer, includes a projection-type image display unit for displaying the image on the screen, a detector for detecting coordinates responsive to the position of the pointer, and a display controller for displaying an image indicating the position pointed by the pointer at position coordinates spaced by a predetermined distance from the position coordinates detected by the detector.
In a preferred embodiment, the image display system includes a modifier for modifying the predetermined distance.
The modifier is preferably a switch.
The pointer may include a plurality of switches, and a combination of the plurality of switches may determine the direction of the position coordinates at the predetermined distance.
Preferably, the modifier modifies the predetermined distance by pointing to a modification display presented on the screen with the pointer.
A detection area of the coordinate detector may be larger than a display image area on the screen by at least a maximum settable value of the predetermined distance.
Preferably, the display controller controls the predetermined distance in response to the position coordinates detected by the detector.
The display controller may control the predetermined distance in proportion to the distance of the position coordinates detected by the detector from the edge of the screen.
To achieve the above object, in another aspect, an image display system of the present invention for displaying an image on a screen in response to a position of a pointer, includes an image display unit for displaying the image on the screen, and a detector for detecting coordinates responsive to the position of the pointer, wherein the pointer includes a plurality of light emitters with one of a hollow section and a transparent section interposed therebetween.
Preferably, the detector detects the center of light quantity from the emitter as the position coordinates pointed by the pointer.
The light emitter is preferably an optical fiber.
The detector preferably detects a peak value position of the light from the optical fiber as the position coordinates pointed by the pointer.